The Prevalence and Impact of Drowsy Driving

This study presents new estimates of the prevalence of drowsy drivers on U.S. roads using data from a nationally-representative survey of drivers, and examines the role of drowsy driving in a nationally-representative sample of crashes subject to in-depth investigations.

November 2010

Suggested Citation

For media inquiries, contact:

Tamra Johnson
202-942-2079
TRJohnson@national.aaa.com

Authors

Background

  • A 2002 survey by the National Highway Traffic Safety Administration (NHTSA) found that 37 percent of drivers reported having fallen asleep or nodded off while driving at some point in their lives, including 11 percent within the past year.
  • Previous analysis of police-reported crashes from 1989-1993 found that approximately 3.6 percent of fatalities and 0.9 percent of all police-reported crashes occurred in crashes that involved a drowsy driver (Knipling and Wang, 1994).
  • According to NHTSA’s 2008 Traffic Safety Facts publication, 2.4 percent of fatal crashes involve a drowsy driver
  • Many traffic researchers believe drowsy driving has been under-reported and underestimated.

The Study

  • This report presents new estimates of the prevalence of drowsy driving on the roads and of the proportion of crashes each year that involve a drowsy driver.
  • The estimated prevalence of drowsy driving among the driving public is based on data collected in the AAA Foundation’s third annual Traffic Safety Culture Index, a nationally-representative telephone survey of 2,000 U.S. residents ages 16 and older, conducted May 11 – June 7, 2010, by Abt SRBI Inc.
  • The estimated proportion of crashes involving a drowsy driver is based on a new analysis of data from the NHTSA’s National Automotive Sampling System Crashworthiness Data System, a nationally-representative sample of crashes involving a passenger vehicle that was towed. Data analyzed was from years 1999 – 2008.

Key Findings

Crash Analysis:

  • An estimated 16.5 percent (one in six) of fatal crashes, 13.1 percent (one in eight) of crashes resulting in hospitalization, and 7 percent (one in fourteen) of all crashes in which a passenger vehicle is towed involve a drowsy driver.
  • Younger drivers age 16-24 were nearly twice as likely to be involved in a drowsy driving crash as drivers age 40-59.
  • Two out of three drivers involved in a drowsy driving crash were men.
  • Vehicles in which the driver was accompanied by a passenger were nearly 50 percent less likely to be involved in a drowsy driving related crash.
  • About 57 percent of drowsy driving crashes involved the driver drifting into other lanes or even off the road.

Survey Results:

  • Seven out of ten (70%) drivers view people driving when they are sleepy as a very serious threat to their safety and nearly all drivers said it was unacceptable (96%) or completely unacceptable (85%) for someone to drive when they were having trouble keeping their eyes open.
  • Two out of five drivers (41%) reported having “fallen asleep or nodded off” while driving at least once in their lifetime; one in ten (11%) reported having done so within the past year, and 4% said they did so in the past month.
  • More than one in four drivers (27%) admitted they had driven while they were “so sleepy that [they] had a hard time keeping [their] eyes open” within the past month.
  • More than half (55%) of those drivers who reported having fallen asleep while driving in the past year said that it occurred on a high-speed divided highway.
  • More than half (59%) of those drivers who reported having fallen asleep while driving in the past year said they had been driving for less than an hour before falling asleep; only one in five reported they had been driving for three hours or longer.
  • More than one in four drivers (26%) who reported having fallen asleep while driving in the past year reported that it had occurred between noon and 5 p.m.
  • Men (52%) were much more likely than women (30%) to report having ever fallen asleep while driving; men (14%) were also more likely than women (8%) to admit having done so in the past year.
  • Drivers age 24 and younger were most likely to report having fallen asleep in the past year, but they were least likely to report having ever fallen asleep. This is consistent with other studies that have found younger drivers to have a higher risk of falling asleep at the wheel.

To remain alert and avoid drowsiness, AAA suggests:

  • Getting plenty of sleep (at least six hours) the night before a long trip;
  • Traveling at times when you are normally awake, and staying overnight rather than driving straight through;
  • Scheduling a break every two hours or every 100 miles;
  • Stop driving if you become sleepy; someone who is tired could fall asleep at any time – fatigue impacts reaction time, judgment and vision, causing people who are very sleepy to behave in similar ways to those who are drunk;
  • Not planning to work all day and then drive all night;
  • Drink a caffeinated beverage. Since it takes about 30 minutes for caffeine to enter the bloodstream, find a safe place to take a 20-30 minute nap while you’re waiting for the caffeine to take effect;
  • Avoid sleepy times of day. Take a mid-afternoon nap and find a place to sleep between midnight and 6 a.m.; and
  • Traveling with an awake passenger.

Symptoms of sleepiness include but are not limited to:

  • Having trouble keeping your eyes open and focused;
  • The inability to keep your head up;
  • Daydreaming or having wandering, disconnected thoughts;
  • Drifting from your lane or off the road, or tailgating;
  • Yawning frequently or rubbing your eyes repeatedly;
  • Missing signs or driving past your intended exit;
  • Feeling irritable and restless; and
  • Being unable to remember how far you have traveled or what you have recently passed

Suggested Citation

For media inquiries, contact:

Tamra Johnson
202-942-2079
TRJohnson@national.aaa.com

Authors